How long does it take transplanted bone marrow to produce enough WBC for protection?

2-3 weeks

What are 3 drawbacks of bone marrow transplants?

Donor T-cells may attack recipient's tissues, recipient's surviving T-cells may attack donor cells, patient must take immunosuppressive drugs for life which increase infection risk & other side effects.

What are some advantages of cord-blood transplants?

Stem cells are easily collected from umbilical cord before birth & can be stored indefinitely. Less likely to cause graft-versus-host disease.